ALBANY, N.Y. (AP) — New York’s financial regulators asked 20 more reinsurance companies Wednesday for information about business with Iran in violation of U.S. sanctions, including measures they’ve taken to ensure they don’t underwrite prohibited shipping.

The Department of Financial Services, which sent a similar letter to 20 other non-U.S. companies a month ago, noted that tougher U.S. economic sanctions took effect July 1. The new law bans financial firms doing business in the U.S. from providing services to companies that trade with Iran.

The department regulates insurers that do business in New York. All 40 insurers that received letters do business in the state and are based outside the U.S.

“Recently, the department learned that several companies have insured trades made with Iran,” department general counsel Daniel Alter wrote. “While these particular transactions may not have violated the sanctions regimes in place in the relevant countries at the time, engaging in a similar transaction now could be found to violate” the new U.S. law.

In January, President Obama signed the law aimed at Iran’s energy, shipping and ship-building sectors and financial services that support them.

State regulators’ letter requested information on the companies’ compliance plans and due diligence programs intended to avoid any potential violations.

Matt Anderson, spokesman for department Superintendent Ben Lawsky, declined to comment Wednesday on the trades cited or any responses to the first 20 letters that were sent in June.

The department last year reached a $340 million settlement with Britain’s Standard Chartered Bank, ending its investigation into U.S. currency transactions routed through the bank’s New York branch for Iranian clients.